1. Field of the Invention
The present invention relates generally to pedalling exercisers, and more particularly, to an exerciser which enables a user to practice various pedalling exercises in a lying-down position.
2. Description of the Background Art
FIG. 8 is a diagram showing the structure of a conventional exerciser by which a user practices pedalling exercise in a lying-down position disclosed in U.S. Pat. No. 4,953,850.
The structure will be described in the following with reference to the figure.
Rotation of a pedal 69 attached to the end portion of a crank arm 71 causes a pedal shaft 3 to rotate. A load device 5 for applying a load to the rotation is provided covered by a frame cover 7 The load device 5 is attached to one end of a center post 11 having a forward lower portion fixed to a leveller pipe 20. Casters 21 are attached to opposite ends of the leveller pipe 20. The other end of the center post 11 is slidable into a seat frame 23 and the end portion of the seat frame 23 is bent in a L-shape manner, constituting a leg 73. Fixed on the seat frame 23 is a seat 29 on which a user who practices pedalling exercise sits. A handle 27 for stabilizing an exercise is attached to the lower portion of the seat 29.
When using the exerciser in practice, an user releases a lock pin 25 to change a sliding position of the center post 11 and the seat frame 23 according to the physique of the user and fixes the lock pin 25 at a position according to his form, thereby determining a positional relationship between the seat 29 and the pedal. Such adjustment allows an appropriate pedalling exercise according to users of various physique.
Although such conventional exerciser, by which pedalling exercise is practiced in a lying-down position as described above, enables an adjustment of space between the seat and the pedal according to the physique of an user, the adjustment is not satisfactory for bringing out a good effect from the pedalling exercise in a lying-down position.
In the pedalling exercise practiced in a lying-down position, the momentum load of the pedalling exercise is changed according to a relative difference in height between the lying-down position, that is, the central position of the pedal shaft and the seat. In other words, when the seat is arranged at a relatively low position with respect to the pedal shaft, a load on the cardiopulmonary function of the user is increased to enable a hard pedalling exercise. On the other hand, the load of the pedalling exercise can be decreased by setting the seat at a position of the same or higher level than that of the pedal shaft, which makes the pedalling exercise suitable for one of rehabilitation exercises for the sick etc. Thus, a seat which can be vertically adjusted with respect to a pedal shaft allows the same device to be used for pedalling exercise practiced in a lying-down position according to a cardiopulmonary function of an user and the condition of a disease of a sick person.
As shown in FIG. 8, a structure of a conventional exerciser by which an user practices a pedalling exercise in a lying-down position, however, has a seat which height can not be adjusted. Thus, it is not easy for the user to practice a pedalling exercise with various loads by using a single exerciser.